If you think that your building’s biggest source of electric use is partitioned away in a furnace room or HVAC area, think again; interior lighting can account for roughly 40 percent of a commercial building’s annual electric cost, making interior lighting systems an obvious target for energy efficient retrofitting. As with most energy efficiency upgrades, there are multiple measures that can reduce the cost of your lighting, beginning with old-fashioned light bulb replacement. But in most buildings, achieving energy efficient lighting on a commercial grade requires the replacement of the old ballasts that can’t accommodate more efficient lamps, repositioning the lamps themselves, and adding sensors to ensure that lighting is not on when it is not needed.

Two types of lighting that are routinely targeted for replacement are fluorescent T12 and metal halide lighting, because they lose significant brightness near the middle of their lifespan but still burn at the same energy level. Whether your building burns with fluorescent T12, metal halide, incandescent, , reducing your electric use and improving your bottom line begins with contacting an energy efficiency provider to perform a lighting audit, after which the best solutions can be identified and implemented.

The level of savings generated by efficient lighting depends largely on the thoroughness of a project. But a first year ROI of 25 to 40 percent or higher is common. As a concrete example of the savings created by lighting retrofits, consider Lime Energy’s energy efficiency lighting retrofit at New York University, which currently generates $589,000 in annual energy savings. The university’s savings result from a 50 percent decrease in original lighting expense. As an added bonus, the retrofit also improves the university’s lighting levels by up to 30 percent, which studies show increases productivity.